The present invention relates to a novel heat-sensitive transfer element being preferably employed to a thermal printing device such as a thermal printer or the like.
Recently, as a printing method using the thermal printing device, the method which comprises overlapping two sheets of thermal paper and forming printed images of the same pattern to each color-developing surface of both thermal papers by Joule's heat generated from a thermal printing head has been proposed.
Such a printing method has various drawbacks as mentioned below.
Firstly, according to the above method, it is impossible to print onto a conventional paper.
Secondly, since the large amount of Joule's heat is required to develop color by heating, a pulse must be conventionally impressed at the pulse width more than 15/1000 seconds in order to obtain a sharp and clear printed image, whereby the printed speed must be carried out at a rate of about 30 characters per second.
Thirdly, the printed image formed onto each color-developing surface of the upper and lower thermal papers is inferior in durability, and is easily alterable.
Fourthly, in order to duplicate the sharp and clear printed image on the lower thermal paper, two sheets of the thermal paper must be closely contacted to each other.